For some computing applications, such as computer networking and telecommunications, it is often necessary to store a large number of computing devices (e.g., switches, routers, servers, etc.) in a relatively small area. To facilitate such a high component density, a number of the computing devices are typically mounted together in a “rack.” A rack may also be referred to as a “chassis” or “cage,” and a variety of such rack mounted installations are known in the art.
An example of a conventional rack 100 is illustrated in FIG. 1. The rack 100 comprises a rectangular-shaped housing 110 having an interior cavity 120 capable of receiving a number of individual computing devices 200, including devices 200a, 200b, . . . , 200f. Each of the devices 200a-f may comprise any type of computing system or device, such as a switch, router, server, etc. Note that one or more of the devices (e.g., devices 200e, 200f) may comprise controller units for the rack mounted installation. The devices 200 may also be referred to as “blades”, “circuit boards”, or simply “boards.” Generally, the term “blade” will be used herein to refer to a computing device that can be received in a rack mounted installation, such as the rack 100 shown in FIG. 1.
The interior cavity 120 of rack 100 is partitioned into a number of bays 130, including bays 130a, 130b, . . . , 130j. Each of the bays 130a-j is capable of receiving a single blade 200 (e.g., blade 200a is disposed in bay 130a, blade 200b is disposed in bay 130b, and so on, but note that bays 1301, 130j are shown empty). The rack 100 usually includes a number of spaced-apart guides 135 for slidably receiving and guiding each received device 200 into its corresponding bay 130. Generally, each blade 200 is inserted into the interior cavity 120 through an open front face 125 of the rack. Various sizes and configurations of racks have been produced, some orienting the blades 200 vertical (as shown in FIG. 1), while others orient the blades horizontal. Also, the rack 100 may include additional devices mounted therein—e.g., power supplies, fans, etc.—that are not shown in FIG. 1 for ease of illustration.
Referring to FIG. 2A, illustrated is one embodiment of a conventional blade 200. The blade 200 includes a board 210 (e.g., a circuit board) or other suitable substrate. Disposed on the board 210 is a number of components 215 (e.g., processing devices, memory devices, and other integrated circuit components, as well as discrete devices such as capacitors, etc.). Attached to the board 210 (or formed integral therewith) is a front panel 220, wherein the front panel is typically mounted at a right angle with respect to board 210. When the blade 200 is inserted into rack 100, a front face 225 of the front panel 220 will be visible and physically accessible from the front face 125 of rack 100. A number of connectors 230 (e.g., electrical or optical connectors) and status indicators 235 (e.g., light emitting diodes, liquid crystal displays, etc.), as well as other components (e.g., keypads, buttons, and other input devices), may be mounted on the front panel 220. Together, the components 215 on board 210, as well as the components mounted on the front panel 220 (e.g., connectors 230 and/or status indicators 235, etc.), comprise a computing system, such as a switch, router, server, or other system.
Although illustrated in FIG. 2A as a board 210 and an attached front panel 220, it should be understood that the blade 200 may comprise a housing. By way of example, as shown in the embodiment of FIG. 2B, a blade 200 may comprise a rectangular housing 205 having the board 210 disposed therein (or having the board forming a wall of the housing), wherein the connectors 230 and status indicators 235 are disposed on a front panel 220 of the housing.
The rack 100 will usually provides a common back-plane (not shown in the figures) to which each of the blades 200 can be connected, thereby allowing each device to communicate with components outside the rack as well as enabling communication between the blades in that rack. To couple a blade 200 to the back-plane, the blade includes one or more connectors 240 (as shown in each of FIGS. 2A and 2B) capable of being connected with (e.g., plugged into) a mating receptacle (or receptacles) disposed on the rack 100. Generally, the mating receptacle (not shown in figures) on the rack 100 is mounted at the rear of the rack's interior cavity 120, and when a blade 200 is inserted into a bay 130 of the rack, the insertion force causes the connector 240 on the blade to plug into the mating receptacle on the rack. The connection between the mating connector 240 and receptacle often provides a significant retraction force, this high interconnect force generally being a by-product of the need for a good electrical connection. The retraction forces may prevent unintentional withdrawal of the connector from the receptacle and, therefore, these forces can inhibit outward movement of the blade 200 itself relative to the rack 100. These retraction forces can be sufficiently high to make ejection of a blade from the rack difficult.
To ease ejection of a blade 200 from the rack 100, the blade 200 may include one or more ejectors 250, as shown in each of FIGS. 2A and 2B. The ejectors 250 may be mounted on the front panel 220 and usually there are two ejectors, one on each side of the front panel. An ejector 250 comprises a device—e.g., a lever or other mechanism providing a mechanical advantage—that can overcome the retraction force of the mating connector 240 and receptacle and, accordingly, that can be used to facilitate ejection of the blade 200 from its corresponding bay 130 of the rack 100. A typical ejector comprises a simple lever having a handle that, when actuated, forces the blade out of the rack (again, by a mechanical advantage obtained by, in this example, the lever). However, these conventional ejectors provide little, if any, additional functionality.